JPH05111632A - High pressure vessel - Google Patents

Abstract

PURPOSE:To prevent fatigue fracture of a high pressure vessel using for pressure disinfecting drinking liquid, etc. CONSTITUTION:Specified slopes are formed on an inside face of an outer cylinder 2 and on an outside face of an inner cylinder 1 along axis direction, and outer cylinder 2 is connected with the outer cylinder 1 closely and engaged sliding freely. An under part of hydraulic ram 5 is fixed to the outer cylinder with a connecting material 5a and a rod 4 which is formed to one body with ram 5 is engaged with a high pressure generating liquid room 13 of the inner cylinder. As the ram is descended, high pressure is generated in the liquid room 13 and, at the same time, an external pressure is generated at the inner cylinder 1 by the action of the outer cylinder 2. At that time, stress amplitude can be reduced by stress acting to the inside and outside face of the inner cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure container which is applied to pressure sterilization of liquids for beverages, isotropic pressurization (consolidation) of powders and the like.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional high-pressure container applied to the pressure sterilization of a liquid for drinking. In FIG. 5, the high-pressure container has a pressurizing cylinder 1'having a liquid chamber 13 'for accommodating a liquid therein, a rod portion 4'providable to be inserted into the pressurizing cylinder 1', and the rod portion 4 '. And a piston 5'in which the rod portion 4'is slidably inserted into the pressurizing cylinder 1 ', a cylinder 6'having the piston 5'built therein and a yoke frame 7', and the like. There is. The liquid pressure treatment in the above apparatus is performed as follows.
That is, the liquid to be treated sent from the supply pipe 10'c passes through the passage 9'c and the check valve 12 'and the liquid chamber 1 of the pressurizing cylinder 1'.
Filled within 3 '. After that, when hydraulic pressure is sent from the hydraulic pipe 10'a to the pressurizing side of the cylinder 6'through the passage 9'a, the rod 4'is lowered together with the piston 5'and pressurizes the liquid.

The liquid has a predetermined pressure (for example, 5000 to 600).
0 kg / cm ² ) for a predetermined time (for example, 20 to 30 minutes)
When the pressure is applied, the hydraulic pressure on the pressurizing side of the cylinder 6'is released, the hydraulic pressure is sent from the hydraulic pipe 10'b to the discharge side of the cylinder 6 ', and the piston 5'is raised to raise the hydraulic pressure in the pressurizing cylinder 1'. After lowering, the processed liquid is discharged to the outside through a discharge path (not shown).

[0004]

By the way, when the liquid pressure treatment is repeatedly carried out for a long period of time using the above-mentioned apparatus, high pressure is repeatedly applied to the pressure cylinder, so that the high pressure container is subjected to high pressure. Will cause important problems such as metal fatigue. However, the conventional measures against metal fatigue have dealt exclusively with the purpose of increasing the wall thickness of the pressurizing cylinder to reduce the stress. However, such measures inevitably increase the size of the device, resulting in an increase in equipment cost. There is also a method in which the pressurizing cylinder is composed of multiple layers and the outer cylinder is shrink-fitted to apply reverse stress in advance. Although this method can reduce the average stress value generated, the stress amplitude can be changed. However, the fatigue strength was not so effective in the high pressure region.

Therefore, the present invention is intended to provide a high-pressure container configured to solve the above-mentioned conventional problems.

[0006]

Therefore, according to the present invention, an inner cylinder for containing a fluid to be pressurized, an outer cylinder closely fitted to the inner cylinder so as to be slidable, and an outer cylinder are provided. An external pressure generating means capable of generating an external pressure in the inner cylinder when slidingly moving with respect to the cylinder; a ram fixed to the outer cylinder and fitted into a fluid storage chamber of the inner cylinder; It is composed of an elevating means for elevating and lowering the ram, which is a means for solving the problem.

[0007]

A predetermined gradient is formed in the axial direction on both the inner surface of the outer cylinder and the outer surface of the inner cylinder, and the outer cylinder is slidably fitted in close contact with the inner cylinder. The lower part of the hydraulic ram is fixed to the outer cylinder, and the rod fixed to the lower part of the hydraulic ram is fitted into the inner cylinder liquid chamber filled with the liquid. When the hydraulic ram is driven and lowered, the outer cylinder also descends in conjunction with the rod, so the hydraulic pressure that is volume-compressed by the rod and rises in the inner cylinder and the external pressure (internal and external) due to the fitting movement of the outer cylinder. The external pressure generated by the gradient in the axial direction formed on the close contact surface of the cylinder) acts simultaneously, and as a result, the stress amplitude generated in the inner cylinder becomes small.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the drawings. FIG. Figure 1
In, the liquid chamber 13 is formed inside the inner cylinder 1,
The inner cylinder 1 is installed on the lower lid 11. Further, a predetermined gradient is formed in the axial direction on the inner surface of the outer cylinder 2 which is slidably and closely fitted to the outer surface of the inner cylinder, and the outer surface of the inner cylinder 1 is also predetermined in the axial direction. A gradient is formed. This gradient constitutes means for generating external pressure in the inner cylinder, and as described later, external pressure can be generated in the inner cylinder 1 when high pressure is generated. Further, a rod 4 which is slidably fitted in the inner cylinder liquid chamber 13 is provided in the lower portion, and a hydraulic ram 5 which moves up and down in the cylinder 6 is connected to the upper surface of the outer cylinder 2 at a lower portion thereof via a connecting member 5a. Has been done. Further, a yoke frame 7 is arranged to bear an axial load, a passage 9c communicating with the inner cylinder liquid chamber 13 is formed in the lower lid 11, and the liquid to be treated supplied from a supply pipe 10c is stored in the liquid chamber. 13 is to be supplied. Reference numeral 12 is a check valve for preventing the backflow of the liquid in the liquid chamber 13. Also, passages 9a and 9b formed in the cylinder cover 8 and the wall of the cylinder 6 are connected to the pressurizing side and the discharge side of the cylinder 6 as the ram raising and lowering means, respectively.
The hydraulic pressure supplied from 10b is sent to the upper and lower surfaces of the hydraulic ram 5, and the hydraulic ram 5 is moved up and down.

This high-pressure container has such a structure that the liquid to be treated supplied from the supply pipe 10c is passed through the passage 9.
c, after supplying and filling the inner cylinder liquid chamber 13 via the check valve 12, hydraulic pressure is sent from the hydraulic pipe 10a to the pressurizing side of the cylinder 6 via the passage 9a to lower the hydraulic ram 5. As a result, the liquid in the liquid chamber 13 is pressurized to a predetermined pressure by the rod 4 and pressure processing is performed. At the same time, since the outer cylinder 2 is also pushed in in conjunction with the rod 4, external pressure acts on the inner cylinder 1.

As described above, in this high-pressure container, the internal pressure Pi due to the liquid and the external pressure Po due to the outer cylinder 2 act on the inner cylinder 1 at the same time during the pressurization process, but at that time, the inner cylinder 1
The circumferential stress σθ and the radial stress σr generated at the inner cylinder 1 are
On the inside, it can be expressed as

Σθ = −2K ² / K ² −1 · Po + K ² + 1 / K ² −1 · Pi

[Number 2] .sigma.r = -Pi where K is the ratio of the outer peripheral radius r _O and inner radius Vi of the inner cylinder 1 K = r _O / Vi. That is, the stresses σθ and σr are generated in the inner cylinder 1 for each pressurizing operation, and by repeating this for a long period of time, a load is repeatedly applied to the inner cylinder 1, which causes fatigue due to the stress. Destruction will occur. Fatigue is evaluated by the change in stress that occurs when the pressure changes from P = 0 to the maximum pressure Pi. here

Σθ−σr = 2K ² / K ² −1 · (Pi−Po) = S S is referred to as Stress Intensity, and the equivalent stress amplitude Sa is

## EQU00004 ## Sa = 1 / 2.multidot.S.

Next, one example of the fatigue strength of the high-pressure container according to the embodiment of the present invention will be calculated by using the above equations. When external pressure Po = 3500 kg / cm ² applied to the internal pressure Pi = 6000 kg / cm ² inner cylinder acting on the diameter ratio K = 1.8 inner cylinder of the inner cylinder, number 1, than the number 2

[Formula 5] σθ = {(1.8 ² +1) / (1.8 ² −1) ・ 60} − {(2 × 1.8 ² ) / (1.8 ² −1) ・ 35} = 12.3 kg / mm ²

[Equation 6] σr = −60 kg / mm ² Substituting this into Equation 4, the equivalent stress amplitude Sa is

Equation 7] Sa = 1/2 {(12.3 + 60)} = 36.2kg / mm 2 stress-strain when the εa = Sa / E = 36.2 / 2 × 10 4 = 1.8 × 10 -3 Here, E is the elastic modulus of the inner cylinder. On the other hand, the trial calculation for the case of the conventional high-pressure container shows that the outer cylinder is shrink-fit and the average stress σm.
When {(maximum stress-minimum stress) × 1/2} = 0 and K = ∞ (however, the inner diameter Vi is the same as in the present invention).

Σa = Sa = 60 kg / mm ²

The Equation 9] εa = 60 / (2 × 10 4) = 3 × 10 -3.

Based on the above calculated values, the stress strain shown in FIG.
When the fatigue strength of the high-pressure container according to the present invention and the conventional high-pressure container is compared from the characteristic curve of the number of repetitions, the present invention: εa = 1.8 × 10 ⁻³ → number of repetitions Nf = 1.5 × 10 ⁵ times Conventional: εa = 3 × 10 ⁻³ → number of repetitions Nf = 3 × 10 ³ times. That is, when pressure treatment is performed with the same liquid pressure, the high-pressure container of the present invention can withstand 50 times longer use than the conventional one.

As described above, in the high-pressure container of the present invention,
The stress amplitude that determines the fatigue strength becomes smaller because the external stress Po acts on the inner cylinder 1 so that the circumferential stress σθ becomes smaller, as is clear from Equation 3. FIG. 3 shows changes in the circumferential stress σθ in the high-pressure container according to the present invention and in the conventional high-pressure container. The solid line shows the case of the conventional single-wall capacity in which only the internal pressure acts, and the two-dot chain line shows the multilayer container. The respective cases are shown. The dotted line shows the case of the high-pressure container according to the present invention. As is clear from this graph, the high-pressure container according to the present invention has a stress (solid line) of the conventional container that is offset by the external pressure indicated by the alternate long and short dash line by σθ.
It can be seen that is decreasing.

[0014]

As described in detail above, according to the present invention, both the inner surface of the outer cylinder and the outer surface of the inner cylinder are formed with a predetermined gradient in the axial direction, and are fitted slidably in close contact with the inner cylinder. The hydraulic ram is fixed to the outer cylinder, and the rod that fits into the liquid chamber of the inner cylinder is fixed to the lower part of the hydraulic ram.Therefore, when driving and lowering the hydraulic ram, it is interlocked with the rod. Since the outer cylinder also descends, the inner pressure of the liquid that is volume-compressed and increased by the rod and the outer pressure based on the pushing of the outer cylinder act on the inner cylinder at the same time, and the stress amplitude generated in the inner cylinder is thereby reduced. Can be made smaller. Therefore, it has an excellent effect that the fatigue strength of the inner cylinder, that is, the high-pressure container is significantly improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a high-pressure container according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of internal and external pressures applied to the inner cylinder of the embodiment of the present invention.

FIG. 3 is a diagram showing a change in circumferential stress of the inner cylinder according to the embodiment of the present invention.

FIG. 4 is a stress-strain-repetition number characteristic curve diagram.

FIG. 5 is a cross-sectional view showing a conventional high pressure container.

[Explanation of symbols]

 1 Inner Cylinder 2 Outer Cylinder 4 Rod 5 Hydraulic Ram 5a Connecting Material 6 Cylinder 7 Yoke Frame 8 Cylinder Cover 9a, 9b, 9c Passage 10a, 10b Hydraulic Pipe 10c Supply Pipe 11 Lower Lid 12 Check Valve

Claims (1)

[Claims] 1. An inner cylinder containing a fluid to be pressurized, an outer cylinder closely fitted to the inner cylinder so as to be slidable, and when the outer cylinder slides with respect to the inner cylinder. An outer pressure generating means capable of generating an outer pressure in the inner cylinder, a ram fixed to the outer cylinder and fitted in a fluid storage chamber of the inner cylinder, and an elevating means for elevating the ram. High-pressure container characterized by.